>>400
まずはこのチェックポイントを確認

https://knowledge.autodesk.com/ja/support/fusion-360/learn-explore/caas/sfdcarticles/sfdcarticles/JPN/How-to-optimize-settings-in-Fusion-360-for-performance.html

https://knowledge.autodesk.com/support/fusion-360/troubleshooting/caas/sfdcarticles/sfdcarticles/Fusion-360-hangs-infinitely-or-crashes-while-creating-sketch.html